JP2005104078A - Vertical mold clamping mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical mold clamping mechanism capable of enhancing mold registering precision even if a tie bar is fine. <P>SOLUTION: The tie bar hole 18 on the side of a movable platen permitting the tie bar 13 to pierce is set to a hole diameter D larger than the outer diameter (d) of the tie bar 13. As a result, a degree of (D-d)/2 permits the movable platen 16 to move left and right in Fig. On the other hand, the guide hole 19 on the side of the movable platen permitting a guide rod 15 to pierce is set to a diameter almost same to the outer diameter of the guide rod 15. By this constitution, since the tie bar receiving mold clamping force and the guide rod for determining the position of the movable platen are separately provided and the horizontal position of the movable platen is determined by the guide rod, positioning precision at the time of mold registering can be enhanced drastically. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mold clamping mechanism essential for an injection molding apparatus.

  In the resin or light metal injection molding method, high-pressure molten resin or molten metal is injected into a mold that is clamped by a mold clamping mechanism. After injection, open the mold and take out the product. The mold generally consists of a fixed mold and a movable mold. Clamping action that presses the movable mold against the fixed mold with a large force, mold opening action that separates the movable mold from the fixed mold and prepares for removal of the molded product, and the mold that combines the movable mold with the fixed mold after removing the molded product The mating action is the main action required for the mold clamping mechanism.

It is important to match the movable mold accurately to the fixed mold by the mold matching action. A structure in which a bearing is attached to a tie bar is known as a technique for enhancing the mold matching action (see, for example, Patent Document 1).
JP-A-7-156232 (FIGS. 1 and 5)

Patent document 1 is demonstrated based on the following figure.
FIG. 7 is a diagram for explaining the basic configuration of the prior art. The support plate 101 and the fixed plate 102 are fixed to the machine base 100 at a predetermined distance, and the tie bar 103. ····························································································· This is a mold clamping mechanism in which the movable mold 107 attached to the movable board 104 is matched with the fixed mold 106 attached to the board 102, and the bearing structure 110 is interposed between the tie bar 103 and the movable board 104. It is characterized by that.

  8 is a cross-sectional view taken along the line 8-8 in FIG. 7, and the bearing structure 110 includes a bush 111 integrally attached to the movable platen 104 side, and abacus bead rollers 112 arranged in the bush 111. Needle bearings 113 ... and triangular grooves 114 ... and flat surfaces 115 ... provided in the tie bar 103 for contact with these rollers 112 ... and needle bearings 113 .... Reference numeral 116 denotes a retainer. The retainers 116... Prevent the rollers 112.

The triangular groove 114 and the flat surface 115 provided on the tie bar 103 can be precisely finished. Since the rollers 112... And the needle bearings 113... Which are precision parts are brought into contact therewith, the radial gap of the diver 103 can be strictly managed. As a result, precise mold matching can be realized.

  However, the mold clamping force generated in the mold clamping cylinder 105 in FIG. 7 acts as a tensile force on the tie bars 103. As a result, the tie bar 103 extends slightly. Then, in FIG. 8, the tie bar 103 becomes slightly thin but a gap is generated between the rollers 112... And the needle bearings 113. It becomes impossible to keep the preload.

  One method for suppressing the amount of elongation of the tie bar 103 is to increase the outer diameter of the tie bar 103. However, increasing the diameter of the tie bar 103 is not preferable because it increases the size and cost of the mold clamping mechanism.

  An object of the present invention is to provide a mold-clamping mechanism that can increase mold-matching accuracy while the tie bar remains thin.

  According to the first aspect of the present invention, a plurality of tie bars are set up on a horizontally arranged support plate, a fixed plate is placed over the top of these tie bars, and a movable plate is arranged in the middle of the tie bar so as to be movable up and down. In the mold clamping mechanism that clamps the mold by pressing the fixed plate, the tie bar hole on the movable plate side through which the tie bar passes is set to be larger than the outer diameter of the tie bar, thereby allowing the movable plate to move horizontally. The guide rod is suspended or raised from the fixed plate or the movable plate to penetrate the movable plate or the fixed plate and the tip of the guide rod is a free end, and the guide hole on the movable plate or fixed plate side through which the guide rod passes is The structure is characterized in that the horizontal movement of the movable platen is limited by setting it to be substantially the same as the outer diameter of the guide rod.

    The invention according to claim 2 is a state in which a movable plate and a support plate are respectively arranged above and below a horizontally arranged fixed plate, a plurality of tie bars are set up on the support plate, and these tie bars are passed through the fixed plate. In the mold clamping mechanism that connects to the upper movable plate and presses the movable plate against the fixed plate, the tie bar hole on the fixed plate side through which the tie bar passes is set larger than the outer diameter of the tie bar By allowing the movable platen and the support plate to move horizontally, the guide rod is suspended or raised from the movable platen or the fixed plate to penetrate the fixed platen or the movable platen, and the tip of the guide rod is a free end. The guide hole on the fixed platen or movable platen through which the rod penetrates is set to be almost the same as the outer diameter of the guide rod, thereby limiting the horizontal movement of the movable platen.

  The invention according to claim 3 is characterized in that a roller bearing is interposed between the guide hole and the guide rod.

  In the invention according to claim 1, the tie bar that receives the clamping force and the guide rod that determines the position of the movable platen are provided separately. Since the tie bar hole through which the tie bar penetrates has a large diameter, the movable plate does not contact the tie bar. For this reason, the tie bar may be thinned, bent or deformed. On the other hand, the guide rod is not connected to the support board by making the tip end free. Therefore, a tensile force does not act on the guide rod. Since the horizontal position of the movable platen is determined by such a guide rod, the positioning accuracy at the time of mold matching can be greatly improved.

  In the invention according to claim 2, the tie bar that receives the clamping force and the guide rod that determines the position of the movable platen are provided separately. Since the tie bar hole through which the tie bar penetrates has a large diameter, the fixed platen does not contact the tie bar. For this reason, the tie bar may be thinned, bent or deformed. On the other hand, the guide rod is not connected to the support board by making the tip end free. Therefore, a tensile force does not act on the guide rod. Since the horizontal position of the movable platen is determined by such a guide rod, the positioning accuracy at the time of mold matching can be greatly improved.

  In the invention according to claim 3, the roller bearing is interposed between the movable platen and the guide rod. Since the roller bearing has a small frictional resistance, the positioning accuracy can be further increased.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a front view of a vertical mold clamping mechanism according to the present invention. A vertical mold clamping mechanism 10 includes a support board 12 disposed horizontally on a machine base 11 and a plurality of (4 Tie bars 13..., A fixed platen 14 hung over the tie bars 13... And a plurality of (four is preferred) guide rods 15 suspended from the fixed platen 14. .., and a movable platen 16 that moves up and down along these guide rods 15... And tie bars 13..., And a mold clamping cylinder 17 that is attached to the support platen 12 as means for raising and lowering the movable platen 16. Basic configuration.

  The tie bar holes 18 on the movable platen side through which the tie bars 13... Are set to have a hole diameter D larger than the outer diameter d of the tie bar 13, thereby allowing horizontal movement of the movable platen 16. One feature.

  Next, the second feature is that the guide rod 15 suspended from the fixed platen 14 and penetrating through the movable platen 16 is a cantilever beam having a lower end as a free end.

  Furthermore, the guide hole 19 on the movable platen side through which the guide rod 15 passes is set to be substantially the same as the outer diameter of the guide rod 15, so that the horizontal movement of the movable platen 16 is limited. And

Reference numeral 21 denotes a ring, and reference numeral 22 denotes a nut. The ring 21 and the nut 22 fix the lower end of the tie bar 13 to the support board 12 and the upper part of the tie bar 13 to the fixing board 14.
Reference numeral 23 denotes a heating cylinder of the injection mechanism, 24 denotes a fixed mold attached to the fixed platen 14, and 25 denotes a movable type attached to the movable platen 16.

  26 is a hemisphere provided at the tip of the piston rod 29 of the clamping cylinder 17, 27 is a spherical seat for housing the hemisphere 26, and 28 is a retaining ring, and the parallelism between the guide rod 15 and the piston rod 29 is incorrect. When there is, the guide rod 15 is made positive, and the movable plate 16 is devised so that it is inclined with respect to the piston rod 29.

  The guide rod 15 may be turned upside down. That is, the guide rod 15 may be extended upward from the movable platen 16 to penetrate the fixed platen 14. In this case, the guide hole 19 is provided on the fixed platen 14 side.

  FIG. 2 is a cross-sectional view showing details of the tie bar holes and guide holes according to the present invention. As described above, the tie bar holes 18 on the movable panel side through which the tie bars 13. The hole diameter D was set larger than the outer diameter d. As a result, the movable platen 16 can be moved to the left and right in the drawing by about (D−d) / 2.

  On the other hand, the guide hole 19 on the movable platen side through which the guide rod 15 penetrates is set to be substantially the same as the outer diameter of the guide rod 15, so that the horizontal movement of the movable platen 16 is limited, and preferably the tie bar 13. And a movable platen 16 are provided with a roller bearing structure 30 (details will be described in the next figure).

  3 is a cross-sectional view taken along the line 3 in FIG. 2, and the roller bearing structure 30 includes a bush 31 integrally attached to the movable platen 16 side, an abacus ball roller 32... And a needle disposed in the bush 31. It consists of bearings 33 ... and triangular grooves 34 ... and flat surfaces 35 ... provided in the guide rod 15 for contacting these rollers 32 ... and needle bearings 33 .... Reference numeral 36 denotes a retainer which prevents the rollers 32... And the needle bearings 33.

  The triangular groove 34 and the flat surface 35 provided in the guide rod 15 can be precisely finished. Since the rollers 32... And the needle bearings 33... Which are precision parts are brought into contact therewith, the radial gap of the guide rod 15 can be strictly managed. As a result, precise mold matching can be realized.

  In addition to the above, the roller bearing structure 30 can also adopt a linear guide mechanism, and is not a sliding bearing, but a roller bearing including rollers such as rollers, needles, conical rollers, balls, etc. The structure of the rollers is arbitrary.

Next, the operation of the vertical mold clamping mechanism having the above configuration will be described.
FIG. 4 is an explanatory view of the overall operation of the vertical mold clamping mechanism of the present invention.
(A) shows the mold open state, and the movable platen 16 is raised by the push-up action of the mold clamping cylinder 17. At this time, since no special horizontal external force acts on the movable platen 16, the movable platen 16 starts to rise while being guided by the guide rods 15.

  (B) shows a state immediately before mold clamping, and shows that the movable mold 25 is smoothly fitted to the positioning pins 38 and 38 extended from the fixed mold 24 by the accurate guide of the guide rod 15. . Further, the movable platen 16 is raised by the mold clamping cylinder 17.

  (C) shows the mold clamping state, and the tie bars 13... Are pulled and extended by the pressing force of the mold clamping cylinder 17. However, since the position of the horizontal position of the movable platen 16 is regulated by the guide rods 15..., The influence of the extension of the tie bars 13.

  By the way, if the lower end of the guide rod 15 is extended and fixed to the support board 12, the mold clamping force also affects the guide rod 15. In order to eliminate this influence, the guide rod 15 is a cantilever beam fixed only to the fixed platen 14, and the lower end is a free end. If the lower end is a free end, no matter how much the tie bar 13 extends, only the guide rod 15 moves upward, and no tensile force acts on the guide rod 15.

Next, it is examined whether or not the present invention can be applied to a horizontal mold clamping mechanism in which the tie bar 13 is placed horizontally.
Since the guide rod 15 is a cantilever beam, the guide rod 15 bends downward when a load is applied downward. When the guide rod 15 is bent, the position accuracy of the movable platen 14 cannot be obtained. On the other hand, in the case of the saddle type described in the embodiment, a downward load does not act on the guide rod 15. For this purpose, the present invention is applied to a vertical mold clamping mechanism.

FIG. 5 is a diagram for studying deformation of the tie bar. The tie bars 13 may be misaligned due to mounting errors, bend under the influence of heat such as a heating cylinder (see reference numeral 23 in FIG. 1), or may be elongated and narrowed during mold clamping.
(A) shows that the center of the tie bar 13 is shifted from the center of the tie bar hole 18 by δ. However, since the tie bar hole 18 has a sufficiently large diameter, there is no concern that the tie bar 13 contacts the movable platen 16.

(B) indicates that the tie bar 13 is bent. However, since the tie bar hole 18 has a sufficiently large diameter, there is no concern that the tie bar 13 contacts the movable platen 16.
(C) shows that the tie bar 13 has become thinner. The narrowing of the tie bar 13 does not affect the movable platen 16 at all.

In the present invention, since the horizontal position of the movable platen 16 is regulated by the guide rod 15, the position accuracy of the movable platen 16 can be greatly improved.
In addition, since the tie bar 13 does not participate in the positioning of the movable platen 16 and only serves as a tension member, the outer diameter can be freely selected and the diameter can be reduced.

Next, another embodiment of the present invention will be described.
6 is a front view of a vertical mold clamping mechanism according to another embodiment of FIG. 1, and the same reference numerals are used for parts common to FIG.
The vertical mold clamping mechanism 10 includes a stationary platen 14 disposed horizontally on the machine base 11, a supporting plate 12 disposed below the stationary platen 14, a movable platen 16 disposed above the stationary platen 14, and a supporting plate. 12, a plurality of tie bars 13... Which are fixed to the movable platen 16 through the fixed platen 14, and a mold clamping cylinder 17 connected to the support platen 12 and the fixed platen 14 are used as basic components. In this mechanism, the molds 24 and 25 can be clamped by lowering the support plate 12 and the movable plate 16 in conjunction with each other by extending the clamping cylinder 17.

  In this mechanism 10, the tie bar hole 18 on the fixed platen 14 side through which the tie bars 13... Are set larger than the outer diameter of the tie bars 13. Then, the guide rods 15 are suspended from the movable platen 16 so as to penetrate the fixed platen 14 and the distal end (in this case, the lower end) of the guide rods 15 is a free end, and the guide rods 15 are penetrated. The guide holes 19... On the fixed platen 14 side are set to be substantially the same as the outer diameters of the guide rods 15... So that the horizontal movement of the movable platen 16 is limited.

The guide rod 15 may rise from the lower fixed platen 14 and penetrate through the upper movable platen 16.
With the above configuration, the same effect as the vertical mold clamping mechanism 10 shown in FIG. 1 can be obtained.

In the first and second aspects, the bush may be directly slidably contacted with the rod without interposing a roller bearing between the guide rod and the movable platen.
Further, the mold clamping cylinder described in the embodiment can be changed to a toggle link.

  The present invention is applied to a vertical injection molding apparatus.

It is a front view of a vertical mold clamping mechanism concerning the present invention. It is sectional drawing which shows the detail of the tie bar hole and guide hole which concern on this invention. FIG. 3 is a cross-sectional view taken along a line 3 in FIG. 2. It is a whole operation explanatory view of the vertical mold clamping mechanism of the present invention. It is a figure which examines a deformation | transformation of a tie bar. It is a front view of the vertical mold clamping mechanism which concerns on another Example of FIG. It is a figure explaining the basic composition of the conventional technology. Sectional view taken along line 8-8 in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vertical mold clamping mechanism, 12 ... Supporting board, 13 ... Tie bar, 14 ... Fixed board, 15 ... Guide rod, 16 ... Movable board, 17 ... Clamping cylinder, 18 ... Tie bar hole, 19 ... Guide hole, 30 ... Roller bearing mechanism.

Claims (3)

  A plurality of tie bars are set up on a horizontally arranged support plate, a fixed plate is placed on top of these tie bars, a movable plate is arranged in the middle of the tie bar, and the movable plate is pushed to the fixed plate. In the mold clamping mechanism that clamps the mold, the tie bar hole on the movable platen side through which the tie bar passes is set to be larger than the outer diameter of the tie bar, thereby allowing horizontal movement of the movable platen, and from the fixed platen or the movable platen. The guide rod is suspended or raised to penetrate the movable platen or fixed platen, the tip of the guide rod is the free end, and the guide hole on the movable platen or fixed platen side through which the guide rod penetrates is almost the same as the outer diameter of the guide rod A vertical mold clamping mechanism characterized in that the horizontal movement of the movable platen is limited by setting to.   A movable platen and a support plate are respectively arranged above and below a horizontal fixed platen, a plurality of tie bars are set up on the support plate, and these tie bars are connected to an upper movable plate with the fixed plate penetrated. In the mold clamping mechanism for clamping the mold by pressing the movable plate against the fixed plate, the tie bar hole on the fixed plate side through which the tie bar passes is set larger than the outer diameter of the tie bar, so that the movable plate and the support plate are supported. Allowing horizontal movement of the panel, the guide rod is suspended or raised from the movable platen or fixed platen to penetrate the fixed platen or movable platen, the tip of the guide rod is a free end, and the fixed platen or movable platen through which the guide rod penetrates A vertical mold clamping mechanism characterized in that the guide hole on the board side is set to be substantially the same as the outer diameter of the guide rod, so that the horizontal movement of the movable board is limited. The vertical mold clamping mechanism according to claim 1, wherein a roller bearing is interposed between the guide hole and the guide rod.

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